<template>
  <div class="star" :class="starType">
      <span v-for="(item,index) in itemClasss" :class="item" class="star-item" :key="index"></span>
  </div>
</template>

<script>
  const LENGTH = 5;
  const CLS_ON = 'on';
  const CLS_HALF = 'half';
  const CLS_OFF = 'off';
  // star 组件思路
  // 1. 接受两个来自父组件的值：星星大小size，评分score
  // 2. 根据size选择不同的class: starType
  // 3. 根据score计算数字转换成三种状态的star：on/ half/ off，依次组成数量为LENGTH的数组
  // 4. 并v-for遍历itemClasses，5个列表依次有不同的class值，渲染不同的star

export default {
    props: {
      score: {
        type: Number
      },
      size: {
        type: Number
      }
    },
    data() {
        return {};
    },
    computed: {
        starType() {
            return 'star-' + this.size;
        },
        itemClasss() {
            let result = [];
            let score = Math.floor(this.score * 2) / 2;
            //console.log(' score ' + score);
            let integer = Math.floor(score) //整数部分
            //console.log(' integer ' + integer);
            let hasDecimal = score % 1 !== 0;  //小数部分
            for (let i = 0; i<integer ; i++) {
                result.push(CLS_ON);//全星
            }
            if (hasDecimal) {
                result.push(CLS_HALF);//有小数则设置半星
            }
            while (result.length < LENGTH) {
                result.push(CLS_OFF);//灰星
            }
            return result;
        }
    }
}
</script>
<style lang="scss" rel="stylesheet/scss">
@import "../../../assets/style/mixin.scss";

.star {
  font-size: 0;
  &.star-48 { // 表示与class='star'同级别 class="star star-48"
    .star-item {
      width: 20px;
      height: 20px;
      margin-right: 22px;
      background-size: 20px 20px;
      &:last-child {
          margin-right: 0;
      }
      &.on { // class="star-item on"
        @include bg-img('star48_on')
      }
      &.half {
        @include bg-img('star48_half')
      }
      &.off {
        @include bg-img('star48_off')
      }
    }
  }
  &.star-36 {
    .star-item {
        width: 15px;
        height: 15px;
        margin-right: 6px;
        background-size: 15px 15px;
        &:last-child {
          margin-right: 0;
        }
        &.on {
          @include bg-img('star36_on')
        }
        &.half {
          @include bg-img('star36_half')
        }
        &.off {
          @include bg-img('star36_off')
        }
      }
  }
  &.star-24 {
    .star-item {
        width: 10px;
        height: 10px;
        margin-right: 3px;
        background-size: 10px 10px;
        &:last-child {
          margin-right: 0;
        }
        &.on {
          @include bg-img('star24_on')
        }
        &.half {
          @include bg-img('star24_half')
        }
        &.off {
          @include bg-img('star24_off')
        }
      }
    }
  .star-item {
      display: inline-block;
      background: no-repeat;
  }
}
</style>
